{"thcode":2,"term":{"code":1718,"name":"impact cratering","parent":101,"scope":"Impact of extraterrestrial objects such as asteroids, comets, and meteorites on Earth."},"uf":[{"name":"asteroid impact","usewith":false},{"name":"bolide impact","usewith":false},{"name":"comet impact","usewith":false},{"name":"meteor impact","usewith":false}],"bt":[{"code":101,"name":"biological and physical processes","parent":1174,"scope":"All continuing activities, functions, and phenomena associated with organisms and non-living matter."},{"code":1174,"name":"topics","parent":1,"scope":"Themes, subjects, and concerns for which USGS information resources are relevant."},{"code":1,"name":"Categories","parent":null,"scope":"Thematic terms for categorizing information resources.  This thesaurus is intended to support finding and understanding scientific information."}],"nt":[],"rt":[{"code":531,"name":"hazards","parent":1174,"scope":"Potential dangers from both natural processes (e.g., earthquakes, floods, and climate change) and human impacts on the environment."},{"code":900,"name":"planetary bodies","parent":1174,"scope":"Large celestial masses of rock, metal, or gas orbiting around a star.  Use for extraterrestrial bodies."}]}